require_dependency "renalware/pathology"

module Renalware
  module Pathology
    # An application service responsible for coordinating the querying of
    # observations and the building of the observation results view model.
    #
    class ViewObservationResults
      def initialize(observations, presenter, descriptions: default_descriptions)
        @observations = observations
        @descriptions = descriptions
        @presenter = presenter
      end

      def call(params = {})
        observations_for_descriptions = find_observations_for_descriptions
        observation_date_series = determine_observation_date_series(observations_for_descriptions)
        paginated_date_series = paginate(observation_date_series, params)
        date_range = build_date_range(paginated_date_series)
        observations = filter_within_date_range(observations_for_descriptions, date_range)
        results = build_results(observations)
        present(results, paginated_date_series)
      end

      private

      def find_observations_for_descriptions
        ObservationsForDescriptionsQuery.new(
          relation: @observations, descriptions: @descriptions).call
      end

      def determine_observation_date_series(observations)
        DetermineObservationDateSeries.new(relation: observations).call
      end

      def paginate(array, params)
        Kaminari.paginate_array(array).page(params[:page]).per(@limit)
      end

      def build_date_range(date_series)
        ObservationDateRange.build(date_series.reverse)
      end

      def filter_within_date_range(observations, date_range)
        ObservationsWithinDateRangeQuery.new(
          relation: observations, date_range: date_range).call
      end

      def build_results(observations)
        Results.new(observations.ordered, @descriptions)
      end

      def present(results_archive, paginator)
        @presenter.present(results_archive, paginator)
      end

      def default_descriptions
        RelevantObservationDescription.all
      end
    end
  end
end